Intermittent stall, now non starter

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pandalooma
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Intermittent stall, now non starter

Post by pandalooma »

Xsara Picasso 1.6 Diesel '06

Occasionally the car would have a momentary hesitation - a complete loss of power - for a quarter second or so. It would then continue as normal. I had the codes read for an unrelated matter and the guy said 'crank sensor' or maybe it was 'cam sensor'. Anyway I did nothing about it, shame on me. The momentary stall was happening more regularly last week, but always picked up and drove normally. Yesterday it was stalling and not picking up, but did re-start. After a few minutes it failed completely and I had it recovered home. It was a non-starter, MIL on. Today it started normally from cold, ran at idle for ten minutes in what I would say was completely normal (it revved ok with no symptoms) then stopped suddenly and will not start. I had noticed that the symptoms were worse when cold before.

I have an almost useless OBDII reader into Scanmaster which says 'no faults' of any description even though the engine management light is on.

Advice on a diagnosis / repair startegy would be welcome.
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GiveMeABreak
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Re: Intermittent stall, now non starter

Post by GiveMeABreak »

You really need a Lexia to diagnose it - generic code readers are limited in what they can do and often can't read many constructor specific codes.

Give Highway Garage a ring in Llandysul - they are Citroen specialists.
pandalooma
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Re: Intermittent stall, now non starter

Post by pandalooma »

I'll do that, thank you... trouble is I expect I will have to get the car over to them, which will need a transporter and I've already spent a ton getting it recovered!
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GiveMeABreak
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Re: Intermittent stall, now non starter

Post by GiveMeABreak »

Ok, so a faulty or weakening camshaft position sensor will ultimately stop the engine from running and prevent starting if it gets to that stage. So they're not that expensive to replace - but do get a decent brand if you can and avoid ECP.
pandalooma
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Re: Intermittent stall, now non starter

Post by pandalooma »

That sounds like a good option, I will start with the cam position sensor. It looks a bit easier to get to than the crank one.
Hell Razor5543
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Re: Intermittent stall, now non starter

Post by Hell Razor5543 »

Do make SURE to get a good make of sensor. There is a saying of "Buy cheap, buy twice". You might also want to avoid buying from Euro Car Parts. Although some forum members have not had problems, other have. ECP has earned the nickname of Euro Crap Parts.
wheeler
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Re: Intermittent stall, now non starter

Post by wheeler »

I've not confirmed if its the same on the DV series engines but on DW engines with EDC15 injection systems the cam position sensor is only used to allow initial starting, it doesn't use it for keeping the engine running, if you unplug it whilst the engine is running the engine will not stop & will run completely normal (albeit with the EML on) until the engine is switched off but then it wont restart.
If you can get the engine running again try disconnecting the cam sensor, if the engine doesn't cut out immediately or start running really badly then I'd probably rule out the cam sensor causing the hesitation.
I'm not saying that it definitely hasn't failed but in my experience cam sensor failure on PSA engines are very rare, in fact I cant think off hand of one I have replaced yet that wasn't due to physical damage caused by a timing belt failure.
Crank sensors on the other hand are definitely more common to fail & can definitely cause hesitation, stalling & a complete non start situation.
I personally though wouldnt replace any parts until a diagnostic & live data read has been done.
pandalooma
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Re: Intermittent stall, now non starter

Post by pandalooma »

Because it seemed relatively easy I replaced the cam sensor first but it made no difference, no start. Symptoms are the same as before replacement. So because I can't get to a code reader I have to move to the 'next most likely' and replace the crank sensor. I wonder if there is a guide to doing this somewhere on the forum? Or an external link?

But maybe before I do that I could hitch up the next-to-useless OBDII reader and look to see if there is any RPM live data on cranking. When I was looking for fault codes with this before it DID show live RPM - that was just before the engine stopped and failed to start. Would it help to check for this?
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GiveMeABreak
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Re: Intermittent stall, now non starter

Post by GiveMeABreak »

Do you have your VIN handy, so we know exactly which engine variant you have? Pop it up here (it will be automatically masked from public view on post submission).

Most of these are at the bottom of the engine on the left hand side for these 1.6 HDis.

The diagram on this post shows the engine Speed Sensor (crank sensor) as item (6) on the diagram:

viewtopic.php?p=585559#p585559

There is a video here on changing a crank shaft sensor generally, so would be a good place to start:

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moizeau
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Re: Intermittent stall, now non starter

Post by moizeau »

That diagram looks the same set up as on my 2.0 HDI regarding the crank sensor. Dead easy job. 10mm spanner is all you need. The hardest thing for you with it not running will be getting underneath it. I used a single car ramp with the steering on full lock, so the ramp doesn't take the front bumper out, to get the front rhs up in the air. When you unplug the sensor give the connector a good coat on contact cleaner spray. Mine was quite oily due to the crank seal weeping. The sensor has a lug that is the primary locating datum and clips into a hole in the crankcase and an oval hole that is the secondary datum and secures it using the m6 bolt.
pandalooma
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Re: Intermittent stall, now non starter

Post by pandalooma »

The VIN is VF7**************[VIN obfuscated, can be read by forum staff] and the replacement crank sensor has not solved the problem so I'm hoping for a 'next move' here!

It still won't start and Scanmaster (for what it's worth) is not reportin any logged faults at all, although it does report that the EML is on.

It also shows engine RPM when I crank it (around 200 RPM on cranking)
It also reports 850kPa fuel rail pressure.

On previous Picassos the Scanmaster HAS reported faults correctly... I wonder if the engine ECU could be at fault? If it is, buying a Lexia code reader wouldn't get me anywhere... would it?
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GiveMeABreak
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Re: Intermittent stall, now non starter

Post by GiveMeABreak »

Ok, so not all generic code readers work with all systems and may only read basic OBDII codes and not the specific constructor-codes.

It's really hard to diagnose from this end as you can appreciate without proper fault codes. Looks like you'll have to get it seen to by someone local with a decent diagnostic kit for the time if you can't get it mobilised.

What about:

http://www.leesautomechanics.com

He's based in Cardigan - maybe worth a call.
wheeler
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Re: Intermittent stall, now non starter

Post by wheeler »

pandalooma wrote:
15 Sep 2021, 12:48
It also reports 850kPa fuel rail pressure.
If the google unit converter I used is correct this is only 8.5 bar?? That's way too low, I'd be wanting to see over 100 bar on cranking.
Do you have any easy start? I'd try & see if it will fire on a sniff of easy start.
NorwegianMan
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Re: Intermittent stall, now non starter

Post by NorwegianMan »

I had exactly the same problem with my XANTIA (X1) 1.8 i 16V. It was the map sensor.
pandalooma
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Re: Intermittent stall, now non starter

Post by pandalooma »

@GiveMeABreak thank you, the guy you suggested came and read the fault codes...

There were several and all could be cleared except:

0501 intermittant fault Transponder Identifier
0504 Int fault transmission signal receiver

I understand these are the engine immobiliser system. Curious. Has there been TWO faults, one of which I have repaired, then another occurring after?

The lead up to this was well defined - occasional stall when driving but only for a fraction of a second. It felt like total lack of power (fuel) which was very brief and the momentum of the car carried it over the problem. Immediately prior to the total failure to start, the engine did run but only for a few minutes. Now of course it will not start at all.

Question: Once the car is started and running, is the immobiliser system active? The mechanic suggested that the immobiliser system could have malfunctioned during normal driving, causing the momentary stalls I was experiencing. Or is the immobiliser system only awake prior to starting? It seems odd that it would be monitoring unauthorised engine activity once the car has started.

If it really is the immob then I think it's a write off sadly, but any last ditch suggestions here are most welcome! Also any work-arounds or tests I could do to further identify the problem.